The invention relates generally to apparatus for separating blood or other biological fluids into their constituent components, such as in plasmapheresis or cell washing. Centrifuges have been developed for the purpose of rapidly, efficiently, and inexpensively effecting this separation in a sterile environment.
It should be noted that while the present system will be described in connection with a plasmapheresis application involving separation of anticoagulated whole blood, other biological fluids and other applications, such as the above-mentioned cell washing process, are contemplated.
A plasmapheresis process is described in U.S. Pat. No. 4,086,924, wherein blood withdrawn from a donor is mixed with an anticoagulant, transported to a rotatable plasmapheresis centrifuge bowl and mounted on a chuck for separation into plasma and non-plasma components. The centrifuge bowl generally comprises a multipiece feed tube and seal assembly with a central input port which introduces whole blood through a longitudinal feed tube into the bottom of the bowl. A central output port is provided to allow the separated plasma to flow out of the bowl. The '924 patent also discloses the use of a standard pressure transducer to monitor fluid pressure in the system.
These bowls disclosed in the prior art have one or more seams in the bowl where the bowl parts have been welded together. These bowls are not well balanced about the rotational axis and require the use of adaptors for fitting the bowl into the chuck for rotation by a motor. The adaptors are normally lined with an elastomeric material for gripping the bowl.
Existing centrifuges for blood processing are typically bulky and too heavy for hand-carried, portable use. Systems typically weigh between 80 and 300 pounds and are transported on platforms with rollers. U.S. Pat. No. 4,412,831, for example, discloses a centrifuge apparatus transported on rollers. A belt driven gear is used to drive the centrifuge bowl. A flexible bearing mount system is used to ensure alignment of the axis of rotation of the rotor with the changing direction of the rotor's angular momentum vector.
In the pending application, U.S. Ser. No. 888,764, filed on July 22, 1986, "PLASMAPHERESIS CENTRIFUGE BOWL" wherein a seamless one-piece bowl body with a rotary seal and header assembly is described. Due to the blow molding process, the balancing of the bowl is maintained within very tight tolerances.